Preparation of trichlorovinyl dichloroacetate

ABSTRACT

Trichlorovinyl dichloroacetate is prepared by reacting a tertiary amine with an excess of dichloroacetyl chloride. Preferably, the reaction is conducted in the presence of an inert diluent.

United States Patent lnventm Jerome M. Lavanhih Akron, ()hln Appl. No732,861

Filed May 29, I968 Patented Sept. 21, 1971 Assignee PPG Industries, Inc.

Pittsburgh, Pa.

PREPARATION OF TRICHLOROVINYL [561 References Cited UNITED STATESPATENTS 3,4l0,892 ll/l968 Martin..l 260/487 2,630,453 3/1953 Gluesenkampet al. 260/487 OTHER REFERENCES Geger et al. Chem. Abstracts Vol. 691968) 86305m Brody & Rae Tetrahydron Letters l6 pp. 1977- i980 1968Brody et al. J. Arg. Chem. Vol. 31, 1966 pp. 626- 628 PrimaryExaminerLewis Gotts Assistant Examiner-Jacqueline L. DavisonAttorney-Chisholm and Spencer ABSTRACT: Trichlorovinyl dichloroacetateis prepared by reacting a tertiary amine with an excess ofdichloroacetyl chloride. Preferably, the reaction is conducted in thepresence of an inert diluent.

PREPARATION OF TRICI'ILOROVINYL DICIILOROACETATE BACKGROUND OF THEINVENTION The preparation of alpha, alpha-dihalocyclobutanones by thecycloaddition of dihaloketene with an olefin has been described inCanadian Pat. No. 740,941. In said patent, dihaloketenes are generatedin situ by the reaction of substantially equal molar quantities of atertiary amine and a dihaloacetyl halide.

BRIEF SUMMARY OF THE INVENTION It has now been discovered that a newcompound, trichlorovinyl dichloroacetate, can be prepared by admixing astoichiometric excess of dichloroacetyl chloride with a tertiary amine.Preferably, the reaction is conducted in the presence of an inertdiluent and at ambient temperatures.

DETAILED DESCRIPTION Any tertiary amine that is free of other functionalgroups which react with dichloroacetyl chloride can be used in thepresent process. Examples of such other reactive functional groupsinclude, for example, -OH, -SH, CO H, NH,

SO H, and SO H. When the preparation of trichlorovinyl dichloroacetateis conducted in the presence ofa diluent, the tertiary amine ispreferably soluble in the diluent selected. Moreover, it is preferredthat the tertiary amine forms a hydrohalide which is relativelyinsoluble in the diluent.

Although simple aliphatic tertiary amines are most preferred, anysuitable tertiary amine (as defined above) can be employed. Thus,ditertiary amines, such as tetramethyldiaminoethane, and cyclic amines,such as pyridine and derivatives thereof, can also be employed.

Aliphatic tertiary amines which suitably can be employed in the presentprocess can be depicted by the following formula:

trimethylamine, triethylamine, tri-n-propylamine, tri-n-bu-.

tylamine, tri-n-octylamine, methyldiethylamine,methylethyln-propylamine, triisopropylamine, dimethylisopropylamine,dimethylbutylamine, dimethylisoamylamine, dimethylisooctylamine,dimethyloctylamine, methylethylisooctylamine,dimethyl-(Z-ethyl)-propylamine, dimethyl-t-butylamine,dimethyloctadecylamine, pyridine, ;lutidine, piperidine, col lidine,picoline, N-methylmorpholine, N-methylpiperidine,

N,N-dimethylipiperazine, quinoline, dimethylaniline, and

dimethylaminoethylpropionate. Preferably, the simple tertiary aliphaticamines, such as triethylamine, are used.

Dichloroacetyl chloride used in the present process is commerciallyavailable and can be prepared by chlorination of acetic acid in thepresence of phosphorus trichloride.

The amount of dichloroacetyl chloride used in the present process is instoichiometric excess based on, the amount of tertiary amine. Thegreater the excess of dichloroacetyl chloride, the better the yield oftrichlorovinyl dichloroacetate. Preferably, the mole ratio ofdichloroacetyl chloride to tertiary amine is at least about 15:1 andpreferably is at least 2:1. Mole ratios in excess of about 5:1 do notincrease the yield appreciably and, therefore, are not ordinarily used.

The preparation of trichlorovinyl dichloroacetate. in accordance withthe present described process is preferably conducted in the presenceofa chemically inert diluent because of the formation of insolubletertiary amine hydrohalides. The formation of solids within the reactionmedium makes stirring difficult and, therefore, the use of a chemicallyinert diluent serves to dilute the reactants and reaction products andallow 2 for more easy separation of the desired product. Preferably,

the chemically inert diluent is also anhydrous since dichloroacetylchloride will react with water and thereby reduce the yield of product.In addition, it is preferred that the inert diluent is also a nonsolventfor the tertiary amine hydrohalide formed as a byproduct of thereaction. To be considered inert, a solvent should contain no functionalgroups that react with the tertiary amine or dichloroacetyl chloridereactants, and with the trichlorovinyl dichloroacetate product.Unsuitable solvents are those containing hydroxyl and/or carboxyl groupsor an active hydrogen, Le, a hydrogen attached to an oxygen, sulfur ornitrogen atom. The amount of solvent employed can vary over a widerange; but, typically should be about three times as great by weight asthe tertiary amine hydrohalide byproduct in order to facilitateagitation of the reaction medium. I

Examples of suitable solvents include: C -C aliphatic hydrocarbons, andchlorinated aliphatic hydrocarbons, C C alicyclics, C C aromatics, andchlorinated aromatics, ethers and esters. Specific examples of the aboveinclude: n-butane, isobutane, pentane, hexane, isopentane, n-heptane,2,2,3- trimethylbutane, n-octane, dodecane, pentadecane, eicosan e,preferably, pentane and hexane; cyclobutane, methylcyclopropane,cyclopentane, cyclohexane, cyclododecane; benzene, toluene, o-xylene,m-xylene, p-xylene, ethylbenzene, n-propylbcnzene, isopropylbenzene,p'-isopropyl-toluene, 1,2,3-trimethylbenzene, 1,3,5-trimethylbenzene,tetrahydronaphthalene, decahydronaphthalene, 1,4-dioxane, 1,3-dioxane,1,3-dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran,methylpropylether, di-n-propylether, di-nbutylether, diiso-propylether,ethyl-n-butylether, diethylether; C,C alkyl esters of C,-C,, carboxylicacids, such as methylacetate, propylacetate, butylacetate,ethylpropionate, methylbutyrate, methyl heptanoate, ethyl benzoate,dimethyl phthalate; carbon tetrachloride, chloroform, perchloroethylene,dichlorodifluoromethane, trichloroethylene, methylene chloride,l,l,l-trichloroethane, 1,2-dichloroethane, o-dichlorobenzene,hexafluorobenzene, monochlorobenzene, and 1,2,4-trichlorobenzene.

In conducting the present described process, it is also advantageous toprovide an unreactive, e.g., anhydrous, atmosphere over the reactionmedium because of the reactivity of dichloroacetyl chloride withmoisture. Typically, unreactive atmospheres can be provided by the useof dry, inert gases such as nitrogen, helium or argon.

The admixing of dichloroacetyl chloride and tertiary amine isadvantageously conducted by adding the tertiary amine to thedichloroacetyl chloride; however, both can be added simultaneously to asuitable reaction vessel. Preferably, the

vtertiary amine is added to a stoichiometric excess of dichloroacetylchloride.

The temperature at which trichlorovinyl dichloroacetate is prepared bythe present process can vary over a wide range and typicallywill dependto a great extent on the diluent employed. Generally, temperatures above-50 C. up to the boiling point of the reaction medium, e.g., C., areemployed. Usually, however, temperatures between about 20 C. and about50 C. are utilized. Typically, temperatures in the range of betweenabout 0 C. and about 30 C. are used, e.g., room temperatures, i.e.,about 25 C., have been found especially suitable.

The pressure at which the present process can be performed will dependto a great extent upon the volatility of the diluent and the reactantsemployed. In general, the reaction can be conducted at normalatmospheric pressure. In the event that one or more of the reactantsand/or diluent have low boiling points, superatmospheric pressures canbe employed, e.g., between about laand about 3 atmospheres. If desired,pressures less than atmospheric can be utilized so long as the reactantsremain in the liquid state.

Trichlorovinyl dichloroacetate prepared in the abovedescribed manner canbe separated easily from the reaction medium by filtering the contentsof the reaction vessel to eliminate solids; concentrating the filtrate;and distilling the resulting concentrate. Conveniently, vacuumdistillation is used for the last step.

Trichlorovinyl dichloroacetate is a water-white liquid having a boilingpoint of 67 C. at 0.9 millimeters of mercury. An infra-red spectrum ofthe compound exhibits maxima at 3007 (C-H bond), 1790 (vinyl estercarbonyl) and 1610 (C=C). A nuclear magnetic resonance spectrum of thecompound exhibited a single peak at 6.15 p.p.m.

Trichlorovinyl dichloroacetate has been found to retard thepolymerization of vinyl compounds, e.g., vinyl chloride monomer. Byincorporating retarding amounts of trichlorovinyl dichloroacetate intovinyl compounds, stabilization of the compound during storage andtransit is accomplished. Moreover, the compound is easily removed fromthe vinyl monomer prior to its polymerization by washing with an aqueousor caustic aqueous solution or by distillation. In the case of emulsionof other aqueous polymerization systems, the step of removingtrichlorovinyl dichloroacetate from the vinyl compound can be eliminatedbecause of its reactivity with water. Typically, from 1 to about percentby weight, based on vinyl monomer, of trichlorovinyl dichloroacetate issufficient to inhibit the polymerization of the monomer. Usually about 5weight percent is employed.

In addition to vinyl chloride, trichlorovinyl dichloroacetate can beemployed to retard the polymerizaton of free radical initiatedpolymerizations, e.g., the polymerization of vinyl compounds such asvinyl acetate and similar esters, styrene, acrylic acid esters, such asmethyl acrylate, and methyl methacrylate, acrylonitrile, and vinylethers, such as vinyl ethyl ether.

The present process and the compound produced thereby are moreparticularly described in the following examples which are intended asillustrative only since numerous modifications and variations thereinwill be apparent to those skilled in the art.

EXAMPLE I A solution of 10.1 grams (0.10 mole) of triethylamine in 50milliliters of dry ether was added over a period of 30 minutes to astirred solution of 32.4 grams (0.22 mole) of dichloroacetyl chloride in100 milliliters of dry ether. The addition was performed at roomtemperature (about C. under a nitrogen atmosphere and the resulting tanslurry stirred for 3 hours. The slurry was then filtered and the filtercake washed with two 50-milliliter portions of ether. The combinedfiltrate and wash solutions were concentrated under vacuum to anamber-colored liquid that weighed 23.2 grams. Vacuum distillation with a6 inch Vigreaux column gave 8.1 grams of water-white liquid (boilingpoint 67 C. at 0.9 mm. Hg.). Analysis of the white liquid by infra-redand nuclear magnetic resonance spectra, as well as carbon, hydrogen,oxygen and chlorine analyses were consistent with the compoundtrichlorovinyl dichloroacetate. Elemental analysis of the compound wasas follows: Calculated for C HCl O C, 18.6; H, 0.4; Cl, 68.7. Found: C,18.6; H, 0.5; Cl, 67.3. Osmometric molecular weight of the water-whiteliquid was found to be 269 (Calculated258). The distillation residue wasfound to be comprised of polymer derived from dichloroketene.

Identification of the water-white liquid product was further confirmedby ethanolysis of the product. Dissolution of 0.8 grams of the productin one milliliter of absolute ethanol followed by removal of thevolatile components under vacuum gave a colorless liquid with aninfra-red spectrum superimposable on that of an authenticdichloroacetate.

sample of ethyl EXAMPLE 11 A suitable 28-ounce polymerization bottle wascharged with 47.5 grams of vinyl chloride, 2.5 grams of trichlorovinyldichloroacetate and 0.015 grams of iso ropyl eroxydic arbonate as a 5percent toluene solution. he po ymerizatlon bottle was capped andweighed prior to placing it in an Ashworth-McDade polymerizer. Thebottle was tumbled at 29 revolutions per minute at 50 C. for 48 hours.After 48 hours, the bottle was vented to the atmosphere to eliminateunreacted vinyl chloride monomer. The bottle was reweighed and found tocontain 10 grams of unrefined polymer. This weight includedtrichlorovinyl dichloroacetate incorporated into the polymer bycopolymerization with vinyl chloride.

The aforementioned procedure was repeated and 9 grams of unrefinedpolymer was found in the polymerization bottle.

EXAMPLE Ill EXAMPLE IV The procedures of Examples I1 and III arerepeated successively with vinyl acetate, styrene, methyl acrylate,acrylonitrile and vinylethyl ether and in each case, trichlorovinyldichloroacetate retards the polymerization of the named vinyl monomer.

While there are above described a number of specific embodiments of thepresent invention, it is obviously possible to produce other embodimentsand various equivalent modifications thereof without departing from thespirit of the present invention.

Having set forth the general nature and specific embodiments of thepresent invention, the true scope is now more particularly pointed outin the appended claims.

1 claim:

1. Trichlorovinyl dichloroacetate.

2. A method of preparing trichlorovinyl dichloroacetate which comprisesadmixing a tertiary amine with a stoichiometric excess of dichloroacetylchloride.

3. A method according to claim 2 wherein the molar quantity ofdichloroacetyl chloride is at least 1.5 times that of the tertiaryamine.

4. A method according to claim 2 wherein the tertiary amine is analiphatic tertiary amine.

5. A method according to claim 4 wherein the tertiary amine istriethylamine.

6. A method according to claim 2 wherein an inert diluent is present.

7. A method according to claim 2 wherein admixing takes place under aninert atmosphere.

8. A method according to claim 2 wherein the temperature of admixing iswithin the range of from 0 to 30 C.

2. A method of preparing trichlorovinyl dichloroacetate which comprisesadmixing a tertiary amine with a stoichiometric excess of dichloroacetylchloride.
 3. A method according to claim 2 wherein the molar quantity ofdichloroacetyl chloride is at least 1.5 times that of the tertiaryamine.
 4. A method according to claim 2 wherein the tertiary amine is analiphatic tertiary amine.
 5. A method according to claim 4 wherein thetertiary amine is triethylamine.
 6. A method according to claim 2wherein an inert diluent is present.
 7. A method according to claim 2wherein admixing takes place under an inert atmosphere.
 8. A methodaccording to claim 2 wherein the temperature of admixing is within therange of from 0 * to 30 * C.